Changing the shape and color of hair represents an important area of modern cosmetics. The consumer uses color-changing agents for the fashionable color design of hairstyles or for the lamination of gray or white hair with fashionable or natural shades.
The person skilled in the art knows various systems for providing color-changing cosmetic agents, in particular for the skin or keratinic fibers such as human hair, depending on the requirements of the coloring or color change.
So-called oxidation colorants are used for permanent, intensive colorings with corresponding fastness properties. Such colorants usually contain oxidation dye precursors, so-called developer components and coupler components. The developer components form the actual dyes under the influence of oxidizing agents or of atmospheric oxygen with each another or with coupling with one or more coupler components. The oxidation colorants are characterized by intensive excellent, long-lasting dyeing results. A mixture of a larger number of oxidation dye precursors can be used for natural-looking colorings, wherein in many cases, further direct dyes are additionally used for shading.
In particular, oxidative hair colorants are often disadvantageous for the user despite their advantageous dyeing properties, so that there is constant need for further development for oxidation dye precursors.
Many compounds have been explored in the search for oxidation dye precursors having a good compatibility profile, but they often suffer from application problems, in particular lack of gray coverage. Moreover, in spite of already highly developed dyeing systems, there is still a need for dyeing systems which achieve excellent brilliance and intensity of coloring, but simultaneously have very good durability, very good fastness properties and excellent homogeneity.
There is a need for improvement in particular in the generation of highly up-to-date shades in the natural shade field.
Many known dyeing systems with which natural shades can be achieved have no satisfactory wash fastness and their skin compatibility is often unsatisfactory.